Even more notable, efforts by educators at nearby Johns Hopkins University to replicate the school’s gains in dozens of other locations have also met with some success. Slowly, the network of Talent Development High Schools is helping student groups that often seem most at risk.

But good news at the high school level is unusual. Despite vigorous calls for change and a host of major reform efforts, encouraging results have been scarce. National Assessment of Educational Progress (NAEP) scores – considered the “Nation’s Report Card” – tend to be stagnant for high-schoolers, even when they rise for elementary school students.

Only about half of low-income and minority students in US high schools graduate, and many of those who do are unprepared for college. The isolated examples of success often fail when administrators or education reformers try to reproduce them on a large scale.

In short, US high schools don’t seem to be working.

“High schools are really large, and it’s harder to coordinate work in them,” says Elaine Allensworth, interim coexecutive director of the Consortium on Chicago School Research. “There’s a different kind of culture in high schools, where teachers think they’re teachers of subjects rather than teachers of students.... And the expectations of high schools have changed dramatically without their general structure changing.”

A new book from the Urban Institute, “Saving America’s High Schools,” examines the results of six major reform efforts and finds little widespread improvement – despite innovative changes and large infusions of money and manpower. And a survey released last month by Deloitte found that while almost half of low-income high school students and their parents say that the primary mission of high school is to prepare them for college, only 9 percent of educators say that’s their primary task.

Focus on high schools is recent

In some ways, the attempt to focus on high school is relatively recent. When the Bill & Melinda Gates Foundation – a major player in high school reform – began focusing on the issue a decade ago, it was “trying to fill a vacuum,” says Vicki Phillips, the college-ready director of education for the foundation. Since then, she says, more players have gotten involved, and the discussion has become more sophisticated. “We’ve gone from talking about dropouts to talking about [how to make graduates] college-ready,” she says.

The Gates Foundation has invested more than $1 billion in improving US high schools, with both noteworthy successes and a number of false starts. In the process, Ms. Phillips says, the foundation has learned a lot about what works and what doesn’t. She still believes as much as ever in the importance of smaller schools, for instance, but the foundation now looks at that as simply one important aspect of a reform effort.

The foundation has also seen how tough it can be to replicate success on a large scale, Phillips says. As a result, it’s putting more emphasis on adapting reform efforts to fit local contexts. And it’s grounding efforts in policies borne out by evidence – such as getting better teachers in the classroom, which research indicates helps drive up student achievement.

But if some gains are being made, many of the reform efforts, no matter how major, have had mixed results.

“I tend to be less encouraged,” says Becky Smerdon, coeditor of the new Urban Institute book, which examined high school reform efforts in Baltimore, Chicago, New York City, North Carolina, and Ohio, and by the Gates Foundation. “In most of the places we looked at and visited, there was an incredible amount of commitment and energy, but they were starting up. The extent to which they were able to take that forward was challenging.”

In all the cases that were examined in the Urban Institute book there were at least some gains, particularly in graduation rates, as well as a shift in culture and a more personalized high school experience. Results from New York City and North Carolina were particularly strong. But widespread improvement and jumps in achievement were elusive.

Ms. Smerdon and others concur on many of the challenges: The large and uncoordinated nature of many high schools results in teachers focusing on their subjects and often having no contact with a student’s other teachers. At the same time, numerous at-risk students enter ninth grade well behind grade level. And the stakes are high: Unlike in the past, when perhaps 30 percent of graduates planned to attend college, today the expectation is that almost all students should go on to some form of postsecondary education.

Students need special attention

A typical US high school operates well if only about 15 percent of the students need extra attention, says Robert Balfanz, codirector of the Everyone Graduates Center at Johns Hopkins and of the Talent Development Middle and High School Project. But in high-poverty neighborhoods, it may be 70, 80, or 90 percent of students who need that help.

Mr. Balfanz advocates block scheduling – in which a group of students share four teachers and take double the usual amount of math and English from the same teacher.

He also recommends an early-warning system that helps catch signs in eighth and ninth grade of students getting off track. Most important, he says, schools have to reorganize so that teachers work with a manageable number of students and so that enough people are available to give extra counseling, tutoring, and other support.

“The hope was that there was always the magic bullet,” Balfanz says. “If you do [reforms] halfway or stop in the middle, you get mixed results.”

Still, there are reasons for some optimism. “I’ve been studying high schools for about 15 years, and for two-thirds of my career, I’ve had to argue why high schools matter,” says Smerdon. “So I’m incredibly optimistic because we’re focused on it, we seem to care about it, and I think there is a commitment to try to change high schools.